Electrical system for controlling the level of liquid in containers



Nov. 19, 1946.

Filed April 12, I943 T. A. CZOHEN ELECTRICAL SYSTEM FOR CONTROLLING THE LEVEL OFLIQUID IN C ONTAINERS 2 Sheets-Sheet l Theod PC A (o/(en INVENTOR) BYJMMM A 13 AZfor M T. A. COHEN Nov. 19, 1946.

ELECTRICAL SYSTEM FOR CONTROLLING THE LEVEL OF LIQUID IN CONTAINERS Filed April 12, 1943 2 Sheets-Sheet 2 771codore ACahen, INVENTO&

WM After-n ey Patented Nov. 19, 1945 more states sh ns PATENT l' 'i'lCE THE LEVEL OF LIQUID Theodore A. Cohen, Chicago,

mesne assignments,

Gompany, @hicago, lit,

L'N QUN'EAINERS ill, assignor, by to Wheelco Instruments a corporation of lllinois Application April 12, 1943, Serial No. i82,8l2

3 Qlaims. 1

This invention relates electrical control apparatus.

One of the objects of my invention is to pro vide improved apparatus for automatically controlling the liquid level or" a container which is under high pressure and temperature.

Another object of this invention is to provide so. A wherein a liquid level responsive s evice controls a vacuum e os illatcr circuit in accordance with impedcc chan es which apparatus does not r"- quire the major portion of the oscillator circuit to be situated in the immediate vicinity of the liquid level responsive device.

Other further objects of my invention will be apparen hereinafter as the re becomes better t rstood from an examination of the in conjunction with the wherein:

detail vi w of inie and connections therefor vlouid level in which is to be a ccrtzolled;

i e 2 is an enlarged detail view partly and partly cut away show ng the impedce as a self-contained unit; tail view of the grid tank unit.

view similar to that of Figure 2 n of the impedancechange device withdrawn slightly from fully assembled position.

Referring to the di particularly,

cecharacter l desi ntainer cona liquid 3 at a le container 5 igure 1) is provided wi chin-g and a e l above the n evel ii and a flange 5 for an opening t aid normal liquid level. nected to the upper flange flange 5 both above below the liquid level 2 therein. These connections comprise an upper pipe E which includes a check valve 8 and a manually e s The impedance change dev ce and als to he lower for communicating with the container 5 is conconnection includes a vertically extend ng elongated hollow cylindrical l2! v c is connected at its side to a pipe 33 which turn connected to the i it. Thu lower d of T ii is connected to a vertical pipe M which in turn is connected to the cerral connection on another T l5. Tie latter T is connected to the flange 5 cock is a check valve ii, The

is cool: an elbow and a T i" pedance change device 6 hroush a rlgh hand side i the it, as shown in Figure l, is connected thro u an elbow E8 to the lower end of the member it. Thus the member l2 co rounioates both above and below the liquid level 0 the container l for maintaining a, liquid level S2 in said member 52 corresponding to the 5 liquid level 2 of the container. The member 92 may he of any suitable cross section but is prefera'oly as shown of angular cross section, such as hexagonal, to facilitate handling in assembly.

e change device 5 includes a grid .lll comprising an inductance 2i and a ca- V as shown in Figures 3 and This t; ice 2? and capacitance are connected electronic oscillator not rinediary oi a concentric do of the inductance El conductor which eX- nected to ground whereon of the conductor ex- 52 to act as a capacity c acity of which varies with 1 :ie liquid in said member. case acts as a dielectric.

ce 2i and capacitance 22 form a ating circuit which is connected oscillator circuit (not r circuit having a plate tank to pred terr 16d. resonant point with t e anlz. capacit change device comprising th ele tode and the grounded if! is connected across the in- The tuning is such as to cau e the oscillator to onen a relay s" itch when the liquid level in the container 5 is at pro-chosen level. As

long as the relay switch is closed, an elect valve cont rues to so the container le the co ty between the i2 and the suraging the de-energizing the circuit of the oscillator to and close the electric feed output 1 re ay sv. L

the liquid level drops below the precontrol level, the capacity between the surfaces faces of lectrode 23h decreases causin a retuning of the oscillator, energizing the relay in the output circuit of the oscillator and closing of the walls in member E2 and the surthe relay switch reopening supply valve. This control process is repeated maintaining liquid at proper level. The mounting of the impedance change device as shown in Figures 2 and 3 is such that it is unaff cted by pressure or temperature 3 of the liquid within the container l and the member l2. This mounting includes a cylindrical member 23 provided with annular corrugations or fins 29. The lower end of the member 28 is welded to the outer edge of a flanged sleeve member 32 which fits over a reduced portion ti The upper end of the corrugated member 28 is closed by an annular late 32 retained on said upper end by screws 35. This plate 34 is centrally apertured co-axially with the member 28 and the member i2 to receive and have mounted thereon a female connector 36 for the grid tank end of the co-axial conductor cable. This conhector member is held in position upon the plate 34 by means of a cooperating member 33 threaded thereto beneath said plate. This me ber 3i acts to clamp a spring clip 38 against the bottom of said plate and in position to support a cylinder as in co-axial relation with the conductor 23 and the axis of members 28 and i2. This cylinder 39 forms the support for the grid tank unit comprising inductance 2i and capacitance 22 hereto-fore referred to. A smaller circular plate of insulating material is mounted beneath th plate t l within the member 23 and is suspended from said plate 35 by means of elongated members til which are connected to the respective plates E i and til by screws t2 and 53, respectively. Th plate id is provided with a central aperture and has mounted thereon above the central aperture an enlarged hollow extension s4 for the conductor 23. This enlarged hollow extension M is adapted to removably receive an upwardly-extending rong tea on a threaded extension at which is removably attached to the up per end of a central electrode 23a.

This central electrode 23a, is mounted in a porcelain member 45 which has an upwardly extending corrugated portion of low leakage path characteristics extending within the member 2i! and a lower portion ll extending within the member i2. These portions 2-6 and Ill are joined by a central enlarged integral portion till having opposed tapered seats 58a and 631). The central electrode 23a is sealed within the porcelain member 55 somewhat in the manner in which the central electrode in an automobile type spark plug is sealed within the porcelain mounting there for. The enlarged portion 58 of the porcelain member s is seated between suitable gaskets in a threaded recess in the upper end of member is and is sealed within said recess by a suitable sealing and retaining annular screw bushing 49. The lower end of the electrode 23a is provided with an enlarged extension 231). This extension 232) is provided with transverse apertures 5i} and is so shaped that the capacity of the condenser formed by the surfaces of said extension and the surfaces of member l2 will increas uniformly as the liquid rises, and decrease uniformly as the liquid recedes to in turn aifect the tuning of the grid tank unit. The apertures 59 cause rapid draining of the liquid dielectric as it recedes preventing a film remaining on the surface of 23?) which might prevent uniform lowering of the capacity, as intended, and consequent interference with true operation. It will be apparent that by virtue of the nature of the sealed mounting for the extended conductor or electrode 23a, extremely high pressures, e. g. upwards of 2,000 lbs. per square inch, within the container l and member 22 will not endanger satisfactory functioning of the equipment.

In the use of high pressure liquid level control equipment high temperatures are usually also present. In order to prevent such high temperatures from interfering with the electrical characteristics of the circuit such as inductance 2i and capacitance 22.

The member 28 is provided with the corrugations or fins 29 of thin section and larg area so that a minimum of heat will be conducted to the electrical system 2 l22 and such heat will rapidly dissipate by radiation and convection from the large corrugated surfaces 29.

By pass system it, H and 13 are designed to prevent th liquid level in the container l2 from ever rising above the top of the electrode 232) with the possibility of coating the skirt 4! of insulator with a film which might prevent true operation of the apparatus. Check valves 8--l'l together with manually operable cocks 9l6 allow easily dismounting of the apparatus exteriorly of said cocks from the container i.

As shown in Figure 3, the plate 34, from which the grid tank unit is suspended, may be readily withdrawn for inspection, renewalor repair of the parts of the grid tank unit. In this connection it will be noted that the ready withdrawal of the grid tank unit is permitted by the fact that prong =5a is slidably inserted in jacket i l. Access to the interior of enclosure l2 and electrode 231) is facilitated by removable collar G9. The operation of the aforedescribed apparatus will be apparent from the above description and by reference to my aforementioned co-pending epplication without further detail;

I am aware that many changes may be made and details varied without departing from the principles of my invention and I, therefore, do not wish to be limited to the details shown and described.

I claim:

1. The combination of a high pressure enclosure having an inner conducting surface adapted to contain liquid at a predetermined level therein, an electrode extending into the enclosure for cooperation by the walls of the electrode with the liquid and said surface to form capacity change device wherein the capacity between the walls of the electrode and surface is varied by the rise and fall of the liquid in accordance with the liquid level, the liquid forming a portion of the electrical capacitance, a non-conducting support for said electrode surrounding the same, the enclosure being provided with an opening and a pressure seal therein for said electrode and support, and a grid tank unit mounted outside said enclosure in spaced relation therewith, and forming an oscillating circuit including said electrode, the mounting for the grid tank unit including an envelope member surrounding the outer end of said electrode and having an opening for receiving the grid tank unit in position upon assembly to readily connect with said electrode.

2. The combination of a high pressure enclosure having an inner conducting surface adapted to contain liquid at a predetermined level therein, an electrode extending into the enclosure for cooperation by the walls of the electrode with the liquid and said surface to form a capacity change device wherein the capacity between the walls of electrode and said surface is varied by the rise and fall of the liquid in accordance with the liquid level changes, the liquid forming a portion of the electrical capacitance, a non-conducting support for said electrode surrounding the same, the enclosure being provided with an opening and a pressure seal therein for said electrode and support, and a grid tank unit mounted outside said enclosure in spaced relation therewith, and forming an oscillating circuit including said electrode, the mounting for the grid tank unit including an annular member surrounding said unit and electrode and having heat radiating fins for preventing heat from interfering with the predetermined characteristics of said unit.

3. The combination of a high pressure enclosure having an inner conducting surface adapted to contain liquid at a predetermined 20 level therein, an electrode extending into the enclosure for cooperation by the walls of the electrode with the liquid and to form a capacity change device wherein the capacity between the walls of electrode and said surface is varied by the rise and fall of the liquid in accordance with the liquid level changes, the liquid forming a portion of the electrical capacitance, a nonconducting support for said electrode surrounding the same, the enclosure being provided with an opening and a pressure seal therein for said electrode and support, a grid tank unit mounted outside said enclosure in spaced relation therewith, and forming an oscillating circuit including said electrode, the mounting for the grid tank unit including an annular member surrounding said unit and electrode and having means for preventing heat from interfering with 

